/*
 * TLS module
 *
 * Copyright (C) 2007 iptelorg GmbH
 * Copyright (C) Motorola Solutions, Inc.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/** Kamailio TLS support :: Module interface.
 * @file
 * @ingroup tls
 * Module: @ref tls
 */

#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include "../../core/locking.h"

#define PARSE_DEF_H /* WOLFFIX class PARSE_ERROR enum */
#include "../../core/sr_module.h"
#include "../../core/ip_addr.h"
#include "../../core/trim.h"
#include "../../core/globals.h"
#include "../../core/timer_ticks.h"
#include "../../core/timer.h" /* ticks_t */
#include "../../core/tls_hooks.h"
#include "../../core/ut.h"
#include "../../core/shm_init.h"
#include "../../core/rpc_lookup.h"
#include "../../core/cfg/cfg.h"
#include "../../core/dprint.h"
#include "../../core/mod_fix.h"
#include "../../core/kemi.h"
#include "tls_init.h"
#include "tls_server.h"
#include "tls_domain.h"
#include "tls_select.h"
#include "tls_config.h"
#include "tls_rpc.h"
#include "tls_util.h"
#include "tls_wolfssl_mod.h"
#include "tls_cfg.h"

#ifndef TLS_HOOKS
#error "TLS_HOOKS must be defined, or the tls module won't work"
#endif
#ifdef CORE_TLS
#error "conflict: CORE_TLS must _not_ be defined"
#endif

/*
 * FIXME:
 * - How do we ask for secret key password ? Mod_init is called after
 *   daemonize and thus has no console access
 * - forward_tls and t_relay_to_tls should be here
 * add tls_log
 * - Currently it is not possible to reset certificate in a domain,
 *   for example if you specify client certificate in the default client
 *   domain then there is no way to define another client domain which would
 *   have no client certificate configured
 */


/*
 * Module management function prototypes
 */
static int mod_init(void);
static int mod_child(int rank);
static void destroy(void);

static int w_is_peer_verified(struct sip_msg *msg, char *p1, char *p2);
static int w_tls_set_connect_server_id(sip_msg_t *msg, char *psrvid, char *p2);

MODULE_VERSION


extern str sr_tls_event_callback;
str sr_tls_xavp_cfg = {0, 0};
/*
 * Default settings when modparams are used
 */
static tls_domain_t mod_params = {
		TLS_DOMAIN_DEF | TLS_DOMAIN_SRV, /* Domain Type */
		{},								 /* IP address */
		0,								 /* Port number */
		0,								 /* SSL ctx */
		STR_STATIC_INIT(TLS_CERT_FILE),	 /* Certificate file */
		STR_STATIC_INIT(TLS_PKEY_FILE),	 /* Private key file */
		0,								 /* Verify certificate */
		9,								 /* Verify depth */
		STR_STATIC_INIT(TLS_CA_FILE),	 /* CA file */
		STR_STATIC_INIT(TLS_CA_PATH),	 /* CA path */
		0,								 /* Require certificate */
		{0, 0},							 /* Cipher list */
		TLS_USE_TLSv1_PLUS,				 /* TLS method */
		STR_STATIC_INIT(TLS_CRL_FILE),	 /* Certificate revocation list */
		{0, 0},							 /* Server name (SNI) */
		0,								 /* Server name (SNI) mode */
		{0, 0},							 /* Server id */
		TLS_VERIFY_CLIENT_OFF,			 /* Verify client */
		0								 /* next */
};


/*
 * Default settings for server domains when using external config file
 */
tls_domain_t srv_defaults = {
		TLS_DOMAIN_DEF | TLS_DOMAIN_SRV, /* Domain Type */
		{},								 /* IP address */
		0,								 /* Port number */
		0,								 /* SSL ctx */
		STR_STATIC_INIT(TLS_CERT_FILE),	 /* Certificate file */
		STR_STATIC_INIT(TLS_PKEY_FILE),	 /* Private key file */
		0,								 /* Verify certificate */
		9,								 /* Verify depth */
		STR_STATIC_INIT(TLS_CA_FILE),	 /* CA file */
		STR_STATIC_INIT(TLS_CA_PATH),	 /* CA path */
		0,								 /* Require certificate */
		{0, 0},							 /* Cipher list */
		TLS_USE_TLSv1_PLUS,				 /* TLS method */
		STR_STATIC_INIT(TLS_CRL_FILE),	 /* Certificate revocation list */
		{0, 0},							 /* Server name (SNI) */
		0,								 /* Server name (SNI) mode */
		{0, 0},							 /* Server id */
		TLS_VERIFY_CLIENT_OFF,			 /* Verify client */
		0								 /* next */
};


/*
 * Default settings for client domains when using external config file
 */
tls_domain_t cli_defaults = {
		TLS_DOMAIN_DEF | TLS_DOMAIN_CLI, /* Domain Type */
		{},								 /* IP address */
		0,								 /* Port number */
		0,								 /* SSL ctx */
		{0, 0},							 /* Certificate file */
		{0, 0},							 /* Private key file */
		0,								 /* Verify certificate */
		9,								 /* Verify depth */
		STR_STATIC_INIT(TLS_CA_FILE),	 /* CA file */
		STR_STATIC_INIT(TLS_CA_PATH),	 /* CA path */
		0,								 /* Require certificate */
		{0, 0},							 /* Cipher list */
		TLS_USE_TLSv1_PLUS,				 /* TLS method */
		{0, 0},							 /* Certificate revocation list */
		{0, 0},							 /* Server name (SNI) */
		0,								 /* Server name (SNI) mode */
		{0, 0},							 /* Server id */
		TLS_VERIFY_CLIENT_OFF,			 /* Verify client */
		0								 /* next */
};


/* Current TLS configuration */
tls_domains_cfg_t **tls_domains_cfg = NULL;

/* List lock, used by garbage collector */
gen_lock_t *tls_domains_cfg_lock = NULL;


int sr_tls_renegotiation = 0;

/*
 * Exported functions
 */
static cmd_export_t cmds[] = {
		{"is_peer_verified", (cmd_function)w_is_peer_verified, 0, 0, 0,
				REQUEST_ROUTE},
		{"tls_set_connect_server_id", (cmd_function)w_tls_set_connect_server_id,
				1, fixup_spve_null, fixup_free_spve_null, ANY_ROUTE},
		{0, 0, 0, 0, 0, 0}};


/*
 * Exported parameters
 */
static param_export_t params[] = {
		{"tls_method", PARAM_STR, &default_tls_cfg.method},
		{"server_name", PARAM_STR, &default_tls_cfg.server_name},
		{"verify_certificate", PARAM_INT, &default_tls_cfg.verify_cert},
		{"verify_depth", PARAM_INT, &default_tls_cfg.verify_depth},
		{"require_certificate", PARAM_INT, &default_tls_cfg.require_cert},
		{"verify_client", PARAM_STR, &default_tls_cfg.verify_client},
		{"private_key", PARAM_STR, &default_tls_cfg.private_key},
		{"ca_list", PARAM_STR, &default_tls_cfg.ca_list},
		{"ca_path", PARAM_STR, &default_tls_cfg.ca_path},
		{"certificate", PARAM_STR, &default_tls_cfg.certificate},
		{"crl", PARAM_STR, &default_tls_cfg.crl},
		{"cipher_list", PARAM_STR, &default_tls_cfg.cipher_list},
		{"connection_timeout", PARAM_INT, &default_tls_cfg.con_lifetime},
		{"tls_log", PARAM_INT, &default_tls_cfg.log},
		{"tls_debug", PARAM_INT, &default_tls_cfg.debug},
		{"session_cache", PARAM_INT, &default_tls_cfg.session_cache},
		{"session_id", PARAM_STR, &default_tls_cfg.session_id},
		{"config", PARAM_STR, &default_tls_cfg.config_file},
		{"tls_disable_compression", PARAM_INT,
				&default_tls_cfg.disable_compression},
		{"ssl_release_buffers", PARAM_INT,
				&default_tls_cfg.ssl_release_buffers},
		{"ssl_freelist_max_len", PARAM_INT, &default_tls_cfg.ssl_freelist_max},
		{"ssl_max_send_fragment", PARAM_INT,
				&default_tls_cfg.ssl_max_send_fragment},
		{"ssl_read_ahead", PARAM_INT, &default_tls_cfg.ssl_read_ahead},
		{"send_close_notify", PARAM_INT, &default_tls_cfg.send_close_notify},
		{"con_ct_wq_max", PARAM_INT, &default_tls_cfg.con_ct_wq_max},
		{"ct_wq_max", PARAM_INT, &default_tls_cfg.ct_wq_max},
		{"ct_wq_blk_size", PARAM_INT, &default_tls_cfg.ct_wq_blk_size},
		{"tls_force_run", PARAM_INT, &default_tls_cfg.force_run},
		{"renegotiation", PARAM_INT, &sr_tls_renegotiation},
		{"xavp_cfg", PARAM_STR, &sr_tls_xavp_cfg},
		{"event_callback", PARAM_STR, &sr_tls_event_callback},

		{0, 0, 0}};

#ifndef MOD_NAME
#define MOD_NAME "tls_wolfssl"
#endif

/*
 * Module interface
 */
struct module_exports exports = {
		MOD_NAME,		 /* module name */
		DEFAULT_DLFLAGS, /* dlopen flags */
		cmds,			 /* exported functions */
		params,			 /* exported parameters */
		0,				 /* exported rpc command */
		tls_pv,			 /* exported pseudo-variables */
		0,				 /* response handling function */
		mod_init,		 /* module init function */
		mod_child,		 /* child initi function */
		destroy			 /* destroy function */
};


static struct tls_hooks tls_h = {
		tls_h_read_f,
		tls_h_encode_f,
		tls_h_tcpconn_init_f,
		tls_h_tcpconn_clean_f,
		tls_h_tcpconn_close_f,
		tls_h_init_si_f,
		tls_h_mod_init_f,
		tls_h_mod_destroy_f,
		tls_h_mod_pre_init_f,
};


static int mod_init(void)
{
	int method;
	int verify_client;

	if(tls_disable) {
		LM_WARN("tls support is disabled "
				"(set enable_tls=1 in the config to enable it)\n");
		return 0;
	}
	if(fix_tls_cfg(&default_tls_cfg) < 0) {
		LM_ERR("initial tls configuration fixup failed\n");
		return -1;
	}
	/* declare configuration */
	if(cfg_declare("tls", tls_cfg_def, &default_tls_cfg, cfg_sizeof(tls),
			   (void **)&tls_cfg)) {
		LM_ERR("failed to register the configuration\n");
		return -1;
	}
	/* Convert tls_method parameter to integer */
	method = tls_parse_method(&cfg_get(tls, tls_cfg, method));
	if(method < 0) {
		LM_ERR("Invalid tls_method parameter value\n");
		return -1;
	}
	/* fill mod_params */
	mod_params.method = method;
	mod_params.verify_cert = cfg_get(tls, tls_cfg, verify_cert);
	mod_params.verify_depth = cfg_get(tls, tls_cfg, verify_depth);
	mod_params.require_cert = cfg_get(tls, tls_cfg, require_cert);
	mod_params.pkey_file = cfg_get(tls, tls_cfg, private_key);
	mod_params.ca_file = cfg_get(tls, tls_cfg, ca_list);
	mod_params.crl_file = cfg_get(tls, tls_cfg, crl);
	mod_params.cert_file = cfg_get(tls, tls_cfg, certificate);
	mod_params.cipher_list = cfg_get(tls, tls_cfg, cipher_list);
	mod_params.server_name = cfg_get(tls, tls_cfg, server_name);
	/* Convert verify_client parameter to integer */
	verify_client =
			tls_parse_verify_client(&cfg_get(tls, tls_cfg, verify_client));
	if(verify_client < 0) {
		LM_ERR("Invalid tls_method parameter value\n");
		return -1;
	}
	mod_params.verify_client = verify_client;

	tls_domains_cfg =
			(tls_domains_cfg_t **)shm_malloc(sizeof(tls_domains_cfg_t *));
	if(!tls_domains_cfg) {
		LM_ERR("Not enough shared memory left\n");
		goto error;
	}
	*tls_domains_cfg = NULL;

	register_select_table(tls_sel);
	/* register the rpc interface */
	if(rpc_register_array(tls_rpc) != 0) {
		LM_ERR("failed to register RPC commands\n");
		goto error;
	}

	/* if (init_tls() < 0) return -1; */

	tls_domains_cfg_lock = lock_alloc();
	if(tls_domains_cfg_lock == 0) {
		LM_ERR("Unable to create TLS configuration lock\n");
		goto error;
	}
	if(lock_init(tls_domains_cfg_lock) == 0) {
		lock_dealloc(tls_domains_cfg_lock);
		ERR("Unable to initialize TLS configuration lock\n");
		goto error;
	}
	if(tls_ct_wq_init() < 0) {
		LM_ERR("Unable to initialize TLS buffering\n");
		goto error;
	}
	if(cfg_get(tls, tls_cfg, config_file).s) {
		*tls_domains_cfg = tls_load_config(&cfg_get(tls, tls_cfg, config_file));
		if(!(*tls_domains_cfg))
			goto error;
	} else {
		*tls_domains_cfg = tls_new_cfg();
		if(!(*tls_domains_cfg))
			goto error;
	}

	if(tls_check_sockets(*tls_domains_cfg) < 0)
		goto error;

	LM_INFO("use wolfSSL version: %08x\n", (uint32_t)(LIBWOLFSSL_VERSION_HEX));
#ifndef OPENSSL_NO_ECDH
	LM_INFO("With ECDH-Support!\n");
#endif
#ifndef OPENSSL_NO_DH
	LM_INFO("With Diffie Hellman\n");
#endif
	if(sr_tls_event_callback.s == NULL || sr_tls_event_callback.len <= 0) {
		tls_lookup_event_routes();
	}
	return 0;
error:
	tls_h_mod_destroy_f();
	return -1;
}


static int mod_child(int rank)
{
	if(tls_disable || (tls_domains_cfg == 0))
		return 0;

	/* fix tls config only from the main proc/PROC_INIT., when we know
	 * the exact process number and before any other process starts*/
	if(rank == PROC_INIT) {
		if(cfg_get(tls, tls_cfg, config_file).s) {
			if(tls_fix_domains_cfg(
					   *tls_domains_cfg, &srv_defaults, &cli_defaults)
					< 0)
				return -1;
		} else {
			if(tls_fix_domains_cfg(*tls_domains_cfg, &mod_params, &mod_params)
					< 0)
				return -1;
		}
	}
	return 0;
}


static void destroy(void)
{
	/* tls is destroyed via the registered destroy_tls_h callback
	 *   => nothing to do here */
}


static int ki_is_peer_verified(sip_msg_t *msg)
{
	struct tcp_connection *c;
	SSL *ssl;
	long ssl_verify;
	WOLFSSL_X509 *x509_cert;

	LM_DBG("started...\n");
	if(msg->rcv.proto != PROTO_TLS) {
		LM_ERR("proto != TLS --> peer can't be verified, return -1\n");
		return -1;
	}

	LM_DBG("trying to find TCP connection of received message...\n");

	c = tcpconn_get(msg->rcv.proto_reserved1, 0, 0, 0,
			cfg_get(tls, tls_cfg, con_lifetime));
	if(!c) {
		LM_ERR("connection no longer exists\n");
		return -1;
	}

	if(c->type != PROTO_TLS) {
		LM_ERR("Connection found but is not TLS\n");
		tcpconn_put(c);
		return -1;
	}

	if(!c->extra_data) {
		LM_ERR("no extra_data specified in TLS/TCP connection found."
			   " This should not happen... return -1\n");
		tcpconn_put(c);
		return -1;
	}

	ssl = ((struct tls_extra_data *)c->extra_data)->ssl;

	ssl_verify = wolfSSL_get_verify_result(ssl);
	// WOLFSSL_X509_V_OK / X509_V_OK
	if(ssl_verify != 0) {
		LM_WARN("verification of presented certificate failed... return -1\n");
		tcpconn_put(c);
		return -1;
	}

	/* now, we have only valid peer certificates or peers without certificates.
	 * Thus we have to check for the existence of a peer certificate
	 */
	x509_cert = wolfSSL_get_peer_certificate(ssl);
	if(x509_cert == NULL) {
		LM_INFO("tlsops:is_peer_verified: WARNING: peer did not present "
				"a certificate. Thus it could not be verified... return -1\n");
		tcpconn_put(c);
		return -1;
	}

	wolfSSL_X509_free(x509_cert);

	tcpconn_put(c);

	LM_DBG("tlsops:is_peer_verified: peer is successfully verified"
		   "...done\n");
	return 1;
}

static int w_is_peer_verified(struct sip_msg *msg, char *foo, char *foo2)
{
	return ki_is_peer_verified(msg);
}

static int ki_tls_set_connect_server_id(sip_msg_t *msg, str *srvid)
{
	if(ksr_tls_set_connect_server_id(srvid) < 0) {
		return -1;
	}

	return 1;
}

static int w_tls_set_connect_server_id(sip_msg_t *msg, char *psrvid, char *p2)
{
	str ssrvid = STR_NULL;

	if(fixup_get_svalue(msg, (gparam_t *)psrvid, &ssrvid) < 0) {
		LM_ERR("failed to get server id parameter\n");
		return -1;
	}

	return ki_tls_set_connect_server_id(msg, &ssrvid);
}

/**
 *
 */
static sr_kemi_xval_t *ki_tls_cget(sip_msg_t *msg, str *aname)
{
	return ki_tls_cget_attr(msg, aname);
}

/**
 *
 */
/* clang-format off */
static sr_kemi_t sr_kemi_tls_exports[] = {
	{ str_init("tls"), str_init("is_peer_verified"),
		SR_KEMIP_INT, ki_is_peer_verified,
		{ SR_KEMIP_NONE, SR_KEMIP_NONE, SR_KEMIP_NONE,
			SR_KEMIP_NONE, SR_KEMIP_NONE, SR_KEMIP_NONE }
	},
	{ str_init("tls"), str_init("set_connect_server_id"),
		SR_KEMIP_INT, ki_tls_set_connect_server_id,
		{ SR_KEMIP_STR, SR_KEMIP_NONE, SR_KEMIP_NONE,
			SR_KEMIP_NONE, SR_KEMIP_NONE, SR_KEMIP_NONE }
	},
	{ str_init("tls"), str_init("cget"),
		SR_KEMIP_XVAL, ki_tls_cget,
		{ SR_KEMIP_STR, SR_KEMIP_NONE, SR_KEMIP_NONE,
			SR_KEMIP_NONE, SR_KEMIP_NONE, SR_KEMIP_NONE }
	},

	{ {0, 0}, {0, 0}, 0, NULL, { 0, 0, 0, 0, 0, 0 } }
};
/* clang-format on */

/**
 *
 */
int mod_register(char *path, int *dlflags, void *p1, void *p2)
{
	if(tls_disable) {
		LM_WARN("tls support is disabled "
				"(set enable_tls=1 in the config to enable it)\n");
		return 0;
	}

	/* shm is used, be sure it is initialized */
	if(!shm_initialized() && init_shm() < 0)
		return -1;

	if(tls_pre_init() < 0)
		return -1;

	register_tls_hooks(&tls_h);

	sr_kemi_modules_add(sr_kemi_tls_exports);

	return 0;
}
